VMware vSphere

 View Only
  • 1.  vmkernel communication - esxi host

    Posted Aug 05, 2022 04:59 PM


    I have three esxi hosts configured with vmkernel iscsi,

    vmkernel isicsi adapters must have communication between all nodes?

  • 2.  RE: vmkernel communication - esxi host

    Posted Aug 06, 2022 03:45 AM

    Your VMK Ports which you would like to use for iSCSI must be able to access your Storage. For iSCSI a IQN Target and a IQN Initiator is needed. Typically a Host runs the Initiator only which means there is no need that the Hosts needs to communicate each other for iSCSI because the act independently.  From a storage perspective this can be totally different because of MPIO or loadbalacing.

    Most type of storages use only a single subnet or 2 subnets and because of redundancy and two or more ports are used on ESXi, so they can technically communicate each other.  There are storages which needs to be configure a subnet per port and if not more Hosts needs to be connected as the storage controller have ports they cant see each other. But that not so common.

    From a VMware vSphere perspective iSCSI is "Ethernet" which always means a fabric aka switch and not iscsi direct connect but it will be dictated by your iscsi storage.




  • 3.  RE: vmkernel communication - esxi host

    Posted Aug 06, 2022 10:39 PM



    The problem I have is an ESXi to which when adding the IQN in the storage it adds it correctly, but on the vCenter side it does not see the volume that I am presenting.

    Testing communication via ssh from the ESXi to the Storage's target IP address through port 3260, the communication fails. I am testing with the nc -z command (From ESXi).

    But I have another Node that adding the IQN to the storage and presenting the volume, when I go to vCenter, that node sees the volume presented, and there is also communication from this node through the target IP of the storage and also through port 3260.

    I have rescanned the adapters, restarted the NODE, added the IP of the storage in the Dinaymic and static Discovery but the node still does not see the storage.

    On a physical level, what other revisions could you carry out?

    Configuring a port binding with two vmkernel adapters that are in the same storage subnet, would it be a good option?

    Any advice would be very helpful. Thanks.

  • 4.  RE: vmkernel communication - esxi host

    Posted Aug 07, 2022 04:46 AM


    1. Test the phys. network
      Try "vmkping IP_OF_SAN -I vmkX" and when configured with jumb frames "vmkping -d -s 8972 IP_OF_SAN -I vmkX".  If you have multiple VMKs(X and Y) than check each one as same when your SAN have multible Ports/IP Addresses
    2. Setup iSCSI
      Configure swISCSI, VMK Binding(only when all IPs in the same Subnet) and dyn. Discovering and based on your SAN Vendor the best practices like No_Delayed_ACK, NOOP Timing and so on.
      Try "esxcfg-rescan -A" on command line or the GUI

    3. Create a ACL on Storage
      You need to create some kind of Host object on your storage based on IQN, IP or ChapUser to specify which Host can see which LUN. Because you tried a rescan from the Host already most SAN showing the Host IQNs in the state. So you can identify your Host
    4.  Access the LUN
      The the rescan again and check vmkernel.log on ESXi or Log on SAN to see if someone tries to connect connect.

    Whats your Storage Vendor and which model you have?